Es photographic light sensitive material having good antistatic properti

ABSTRACT

A SILVER HALIDE PHOTOGRAPHIC LIGHT-SENSITVE MATERIAL ENDOWED WITH GOOD ANTISTATIC PROPERTY BY INCORPORATING IN THE PHOTOGRAPHIC EMULSION LAYER OR APPLYING TO THE SURFACE OF THE SUPPORT FOR THE PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL A POLYHYDRIC ALCOHOL ESTER DERIVATIVE OF AN ALPHA-SULFOFATTY ACID HAVING THE GENERAL FORMULA   (R-CH(-SO3-M)-COO)N-Y   WHEREIN R IS A SATURATED OR UNSATURATED STRAIGHT OR BRANCH CHAIN ALIPHATIC GROUP HAVING MORE THAN 6 CARBON ATOMS; M IS A HYDROGEN ATOM, AN ALKALI METAL ATOM, OR A QUATERNARY AMMONIUM GROUP; Y IS A RESIDUAL GROUP HAVING AT LEAST ONE HYDROXYL GROUP AND FROM 2 TO 18 CARBON ATOMS; AND N IS AN INTEGER OF FROM 1 TO 7.

"United States Patent Oifice 3,756,828 Patented Sept. 4, 1973 3,756,828 PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL HAVING GOOD ANTISTATIC PROPERTIES Masakazu Yoneyama, Nobuo Yamamoto, and Koutaro Endo, Minami Ashigara-Machi, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan No Drawing. Filed Mar. 8, 1972, Ser. No. 232,941 Claims priority, application Japan, Mar. 11, 1971, 46/ 13,315 Int. Cl. G03c 1/82 US. Cl. 96-87 A 9 Claims ABSTRACT OF THE DISCLOSURE A silver halide photographic light-sensitive material endowed with good antistatic property by incorporating in the photographic emulsion layer or applying to the surface of the support for the photographic light-sensitive material a polyhydric alcohol ester derivative of an alpha-sulfofatty acid having the general formula wherein R is a saturated or unsaturated straight or branch chain aliphatic group having more than 6 carbon atoms; M is a hydrogen atom, an alkali metal atom, or a quaternary ammonium group; Y is a residual group having at least one hydroxyl group and from 2 to 18 carbon atoms; and n is an integer of from 1 to 7.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a silver halide photographic light-sensitive material having good antistatic properties.

Description of the prior art A photographic light-sensitive material is generally prepared by coating one or more light-sensitive photographic emulsion layers and subsidiary layers to the surface of a film of a poly-alpha-olefin such as polyethylene or polystyrene, a cellulose organic acid ester such as cellulose triacetate, or a polyester such as polyethylene terephthalate; the surface of a baryta-coated paper; or the surface of a sheet prepared by coating both surfaces of a paper with such a polymer as described above. Therefore, such photographic light-sensitive materials have considerable electrical insulation. Consequently it frequently happens that when the surface of the photographic light-sensitive material is rubbed against each other or rubbed by the surface of a foreign material during the manufacturing or the use of the material, electrostatic charges accumulate on the photographic material.

The accumulated electrostatic charges give rise to various disadvantages. For instance, when the accumulated electrostatic charges on a photographic light-sensitive film are discharged before development, the light-sensitive emulsion layer of the photographic film is exposed to the discharged light and spot-like or dendroid stains are formed on the photographic emulsion layer on development. Such stains are generally called static marks and the occurrence of the static marks reduces greatly or sometimes results in a complete loss of the commercial value of the photographic film. Because the presence of static marks cannot be confirmed before development, it is a quite troublesome problem.

Furthermore, the electrostatic charges accumulated on a film support or on the material during coating cause the ducing a secondary difficulty such as an unevenness in coating on application of the photographic emulsions.

In fact, these electrostatic charges are formed when a photographic film or paper is brought into contact with and rubbed by rollers or when the back surface of a photographic film or paper is brought into contact with and then separated from the surface of the photographic emulsion layer thereof during the rolling or unrolling step of the photographic film or paper.

In manufactured photographic products, these electrostatic charges are also formed when the back surface of a photographic film is brought into contact with the emulsion layer thereof and then separated therefrom as in rolling or unrolling of the photographic material which under high humidity conditions results in the adhesion of the photographic material to each other, when the surfaces of a photographic cine-film are rubbed by mechanical parts, when the back surface of the cine-film is brought into contact with the emulsion layer thereof and separated therefrom at the photographing or unrolling stage of the cinefilm, or when an X-ray photographic film is rubbed by mechanical parts or is separated from a fiourescent sensitizing paper in an automatic photographing machine. Furthermore, electrostatic charges are formed on photographic light-sensitive films or papers when they are brought into contact with packing materials.

The actual occurrence of static charges by friction of the materials against each other or the separation of them from each other after they are brought into contact is believed to be based on the ionic properties of the materials to be brought into contact but it is difficult at present to determine chemically what kind of materials are charged positively and what kind of materials are charged negatively. However, it can be easily supposed that the formation of such electrostatic charges can be prevented by increasing the electric conductivity on the surface of the materials to eliminate the static charge in a short period of time.

Therefore, it has hitherto been attempted to increase the conductivity of the supports or the various surface layers of photographic emulsions of photographic lightsensitive materials and the use of various hygroscopic materials, water-soluble inorganic salts, surface active agents, and the like has been attempted. However, such materials show ditferent properties with different photographic emulsions or different photographic compositions. That is to say, some materials which provide good antistatic effects with some specific photographic emulsions or specific materials of photographic compositions do not provide antistatic effects with other photographic emulsions or other materials for photographic compositions or further sometimes adversely affect the photographic properties of photographic light-sensitive materials containing them.

In general, there are few materials which give satisfactory antistatic effects to high-sensitive photographic emulsions under particularly low humidity conditions, that is to say, the antistatic properties of some materials decrease with the passage of time or adhesion difficulties at a high temperature can result with some materials. Thus, the application of antistatic materials to photographic light-sensitive materials is accompanied with quite difficult problems and the use of these materials is usually limited to a narrowed portion of the field of antistatic materials. Accordingly, the application of many different types of antistatic agents to photographic light-sensitive materials has been proposed.

An object of this invention is, therefore, to provide a photographic light-sensitive material on which the formation of static charges has been markedly reduced without resulting in adverse influences on the photographic properties thereof.

3 SUMMARY OF THE INVENTION As the results of a wide-range of investigations of antistatic agents, the inventors have discovered that the above objects of this invention can be attained by incorporating in at least one layer of the silver halide emulsion layers, an anti-curling layer, and an anti-halation layer and/or by applying to at least one surface of the support for a photographic light-sensitive material a multihydric alcohol ester derivative of an alpha-sulfofatty acid, that is, the ester of an alpha-sulfofatty acid and a polyhydric alcohol having more than one hydroxyl group as an alcohol residual group as represented by the following general formula wherein R represents a saturated or unsaturated, branched or straight chain aliphatic group having more than 6 carbon atoms; M represents a hydrogen atom, an alkali metal atom, or a quaternary ammonium group; Y represents a residual group having at least one hydroxyl group and from 2 to 18 carbon atoms; and n represents an integer of from 1 to 7.

DETAILED DESCRIPTION OF THE INVENTION The aliphatic saturated or unsaturated branched or straight chain group R in the above general formula usually is an alkyl or alkenyl group having from about 6 to about 20 carbon atoms. Suitable such examples are hexyl, octyl, tertoctyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, hexadecenyl octadecyl and eicosyl. Examples of the residual group represented by Y in the above formula include the residual groups of an alkanediol such as ethylene glycol, propylene glycol, butylene glycol and the like; polyethylene glycol; 1,4-dicyclohexane dimethanol; an alkanetriol such as glycerol, 1,2,3-butanetriol, 1,2,6- hexanetriol, etc.; a trimethylol alkane such as trimethylol propane; a multihydric alcohol such as sorbite, sorbitol, sorbitane, 2,2,6,6-tetramethylol cyclohexanol, pentaerythritol, saccharose, rafiinose, and the like.

A characteristic fact is that when the compound of the above-described formula is one in which Y is a residue containing no hydroxyl group, e.g., containing an ethyl group, such a compound has no antistatic effect, while the compounds of this invention in which Y is a residue containing a hydroxyl group show quite excellent antistatic effects.

Among the compounds represented by the above general formula, those compounds wherein Y is a residual group of sorbitol, sorbitane, or saccharose are most preferred.

Suitable alkali metals for M are sodium and potassium. The term quaternary ammonium group is intended to cover both NH, and substituted ammonium groups having one or more substituents for example, short chain alkyl or hydroxy-alkyl groups such as methyl, ethyl and hydroxyethyl. Specific examples are (CH NH+ and (CH CH OH) NH+.

Suitable specific examples of the compounds of this invention represented by the above general formula are illustrated below.

Compound 1:

CHH CHC O O CH;(CHOH)4CH H SOaNa Compound 2 G H CHC O 0-sorbitan residual group SOaNa Compound 3:

CmH iCHCOOCH CH(OH)CH;OH

SO H

omon onzon Compound 7 CIIgOH crrzoocno n SOaNa Compound 8:

CHH CHC O O CHACHOHMCH O 0 00110 11 SOsNa SO3Na Compound 9 C H OHCOO CIIQCIIQ SOaNa HOIIZCHZC CHzCHz O H CH CHzOH Compound 10:

C H CHCO 0-saccharose residual group SOsNa Compound 11 [C H CHC O O saccharosc residual group [CHHZQCI'IC 0 O-saccl|arosc residual group SOBNQ J [CHHZDCHCO O sacchamse residual group SO Na Compound 1-1:

C 6H C HC 0 0saecliaroso residual group SO Na Compound 12 Compound 13 Compound 15:

C H CHC O Orafinoso residual group SO Nfi Compound 16 [CHHQOCHC O O rafiinose residual group SO Na J3 The compounds used in this invention may be prepared by various methods but are more profitably prepared by the methods described in The Journal of the American Oil Chemist Society, 45, 549-551 (1969) and ibid.; 45, 78-79 (1968). In this case, the product may be obtained, as the case may be, as a mixture of a mono ester and a polyester according to the conditions for the reaction since the product is an ester with a polyhydric alcohol but such a mixture can also be used effectively as an antistatic agent.

By the present invention the difliculties caused by static marks during the production of photographic light-sensitive materials or during use of them can be eliminated. For instance, by incorporating a compound of this invention in a photographic light-sensitive film, the formation of electrostatic charges in placing the film in a cassette (magazine) or in mounting the magazine in a camera is very effectively prevented even under low humidity conditions. The antistatic property of the film is not reduced with the passage of time. Moreover, the compound of this invention has the advantage that it provides a high electric conductivity to photographic films and papers and causes no difficulties in adhesion even at high temperatures.

The compound of this invention can be easily dissolved in such solvents as water and methanol and by adding it to photographic emulsion layers of a photographic lightsensitive film or paper or by applying it to the surface of a support for a photographic light-sensitive film or paper, the occurrence of electrostatic charges can be effectively prevented without giving rise to adverse effects on photographic properties such as sensitivity, gamma, and fog as well as properties such as the viscosity, the coagulation temperature, and the pH of photographic emulsions.

The amount of the compound can be varied according to the kind and shape of the photographic film or paper or the manner of applying the photographic emulsion to a support. However, it is preferred that the compound used in this invention be present in a photographic lightsensitive film or paper in an amount of from about 0.01 to about 2.0 g., preferably from about 0.04 to about 0.4 g. per square meter of the film or paper. The compound used in this invention may be incorporated in any gelatincontaining layers of a photographic light-sensitive material, such as silver halide emulsion layer, a protective layer, an anti-halation layer, an undercoat, a backing layer, and the like, but is preferably incorporated in a surface layer of the light-sensitive material. Moreover, the compound of this invention can be effectively applied to the surface of a film support such as a cellulose triacetate film, a polyethylene terephthalate film, and the like, the surface of a paper, and the surface of a sheet prepared by coating a paper with a polymer such as polyethylene.

When the compound of this invention is incorporated in the photographic layer of a photographic light-sensitive material, it can be incorporated into the emulsion to be used for the layer as a solution in water, in an organic solvent, or in a mixture thereof, it can be sprayed or applied onto the surface of the photographic layer, or the photographic light-sensitive material having photographic emulsion layers already prepared thereon can be immersed in a solution of the compound and dried.

When the compound of this invention is applied to the back surface of a film base for a photographic lightsensitive material, a solution of the compound in water, an organic solvent such as methanol, or a mixture thereof can be sprayed or applied onto the back surface of the support or the film base may be immersed in a solution of the compound and dried. Also, if necessary, the compound of this invention may be used together with a binder such as gelatin, polyvinyl alcohol, cellulose acetate phthalate, cellulose acetate, or other various polymers.

The compound of this invention can be used to prevent the formation of static charges on films or other shaped articles of polymers such as cellulose esters, polyesters, polystyrenes, polycarbonates, polyethylenes, polypropylenes, and other vinylic resins. Furthermore, it has been found that the compound used in this invention is also excellent as a wetting improving agent necessary for applying photographic coating compositions to a support at high speed.

The antistatic properties of the compound of this invention were evaluated in the following examples using a method in which a film strip containing the compound, adjusted to a relative humidity (RH) of 20 to 65%, was rolled by a gum roller and the amount of electrostatic charges formed were measured using a Faraday box. This method comprised placing an unexposed photographic light-sensitive film containing the compound on a rubber sheet, pressing the film onto the rubber sheet using a gum 6 roller, and thereafter separating the film from the rubber sheet to form static marks. A measurement of the surface specific resistance was also made.

This invention will now be further explained in greater detail by reference to the following examples which are to be interpreted as illustrative and not limiting the invention. All percentages and parts are by weight unless otherwise indicated.

Example 1 An X-ray photographic light-sensitive material (Specimen No. 10) prepared by coating continuously an undercoated cellulose triacetate support with a high-sensitive emulsion for X-ray photograph containing 6% gelatin and 6% silver iodobromide and an aqueous solution of gelatin containing no antistatic agent as the surface protective layer and dried was immersed in a 1% aqueous solution of one compound of this invention (Compounds 1, 2, 6, 8, l0, 11, or 15 described above) for 30 seconds and dried to provide Specimens No. 1, No. 2, No. 3, No. 4, No. 5, No. 6 and No. 7, respectively.

Also, for the purposes of comparison, Specimen No. 10 described above was treated in a manner as above with a 1% aqueous solution of saponin or alpha-sulfopalmitic acid methyl ester which is similar to the compound of this invention to provide comparison specimens (Specimen No. 8 and Specimen No. 9, respectively).

Each of the specimens thus prepared was adjusted to a relative humidity of 40% and then passed into a Faraday gauge through a space between the two gum rollers, wherein the amount of the static charges formed was measured using a vacuum voltmeter. Also, each of the photographic film samples prepared above was placed on a white rubber sheet and after rolling the surface of the white rubber plate with a roller to provide a definite friction under the conditions of 23 C. and 40% relative humidity, the white rubber plate was separated from the film. Each of the photographic film samples was then developed in a developing solution having the following composition for 4 minutes at 20 C. and then the amount of static marks thus formed was measured, whereby the antistatic properties of the compound were evaluated.

The results obtained in the above experiment are shown in the following table.

TABLE 1 WHO WHO

Charged amount (volts) Specimen number Compound number sulfopalmitate. 10 None (control) E Evaulation of antistatic properties shown in the above table:

A: The formation of static marks was not observed.

B: Static marks were formed slightly.

C: Static marks were formed considerably.

D: Static marks were formed remarkably.

E: Static marks were formed over the entire surface of the photographic film sample.

As is clear from the results shown in Table 1, in the photographic films (Specimen Nos. 1-7) treated with the aqueous solution of a compound of this invention, either no or only a slight formation of static marks was observed in the static charge formation test, whereas in the case of the control samples (Specimen Nos. 8 and 9) containing saponin or alpha-sulfopalmitic acid ester respectively, static marks were formed remarkably and in the control sample (Specimen No. 10) not treated with any aqueous solution of an antistatic agent, static marks were formed on the entire surface thereof.

Example 2 A high-sensitive silver halide emulsion for negative use containing 6% gelatin and 12% silver iodobromide was mixed with a 4% aqueous solution of saponin as a wetting agent in an amount of S m1./kg. of the emulsion and the mixture was applied to an undercoated cellulose triacetate film support.

A coating composition for the surface protective layer prepared by adding 70 ml. of a 5% aqueous solution of a compound of this invention (Compound 1 shown above) to 1 kg. of an aqueous 7% solution of gelatin was applied to the silver halide emulsion layer thus formed. After setting by cooling, the sample was dried.

For the purposes of comparison, a comparison sample of photographic film was prepared by applying a surface protective gelatin layer using 100 ml. of a 4% aqueous solution of saponin or 70 ml. of a 5% aqueous solution of alpha-sulfopalmitic acid methyl ester in the same manner as described above. The antistatic faculty and the amount of static charges formed for each of the photographic films were measured using the methods described in Example 1.

The results obtained are shown in the following table.

TABLE 2 Charged amount (volts) Static Compound marks Example 3 1 g. of a compound (Compound 11 as shown above) of this invention was added to 90 ml. of distilled water and the solution was added to a solution prepared by dissolving 2 g. of cellulose acetate phthalate and 2 g. of triethanol amine in 600 ml. of methanol.

The solution thus prepared was applied to the back surface of a cellulose triacetate film and then a negative silver halide emulsion, containing 7% gelatin and 7% silver iodobromide, for cine-film was applied to the opposite surface of the film.

The surface specific resistance of the back surface of the photographic light-sensitive film thus prepared at a relative humidity of 30% was 5 10 ohms, which was much lower than the surface specific resistance (8X10 ohms) of the back surface of a control photographic film of the same composition but having no backing layer containing the compound of this invention.

Example 4 0.2 g. of chrome alum and 0.4 g. of saponin were added 2 kg. of an aqueous 2% gelatin solution and the solution obtained was divided into two parts. 30 ml. of

a 5% aqueous solution of a compound of this invention (Compound 1) was added to one of them, while ml. of a 5% aqueous solution of saccharose monolauric acid ester, a known antistatic agent, was added to the other part. Each of these two solutions was applied as a protective layer to a high-sensitive emulsion layer, containing 6% gelatin and 6% silver iodobromide, for X-ray photography formed on a polyethylene terephthalate film support and then dried.

The antistatic properties and the amount of electrostatic charge build up of the X-ray photographic films thus obtained were measured at a relative humidity of 65% and the results are shown in the following table.

TABLE 3 Charged Static amount Compound marks (volts) Compound 1 A 10 saccharose monolauric acid ester C 15 None (control) E 21 Example 5 30 ml. of a 5% aqueous solution of a compound of this invention (Compound 12) was added to a 6% aqueous solution of gelatin containing an antihalation dye, 3- methyl-4-(p-dimethylaminobenzylidene) 1 (4 sulfophenyl)-pyrazolone and, after further adding thereto 0.4 g. of chrome alum and 0.1 g. of saponin, the mixture was applied to a cellulose triacetate film base and dried. A high-sensitive negative photographic emulsion, containing 7% gelatin and 8% silver iodobromide, was applied to the opposite surface of the film and then a mixture of 1 kg. of aqueous 2% gelatin solution and 100 ml. of 5% aqueous solution of the compound of this invention (Compound 10) was further applied to the emulsion layer as a protective layer. After drying the layers, the amount of static marks under a relative humidity of 30% was measured and the antistatic properties were determined from the amount of the static marks in the same manner as disclosed in Example 1. The results are shown in the following table.

As is clear from the results shown in the above table, a photographic film having a protective layer containing a compound of this invention and an anti-halation layer containing the compound of this invention showed excellent antistatic properties.

Example 6 4% aqueous solution of saponin was added to a highsensitive silver halide emulsion for negative film use containing 7% gelatin and 8% silver iodobromide and the mixture was applied to an undercoated cellulose triacetate film support. After the layer was set, a mixture of 1 kg. of an aqueous 2% gelatin solution and 70 ml. of a 5% aqueous solution of a compound of this invention (Compound 1) was applied to the emulsion layer and, after the layer was set, was dried.

The photographic film was placed under a condition of 2 0% relative humidity and then the film was passed through a high speed camera. Thereafter, the formation of static marks was measured. The results obtained are shown in the following table.

TABLE Compound Static marks in the camera test Compoundl N0 static marks over the entire length of 122 meters.

None (control) Static marks were formed markedly at the end of the film.

A color photographic film for negative film use prepared by applying continuously to a support a color photographic high sensitive emulsion containing a color coupler and an aqueous gelatin solution containing no antistatic agent as the surface protective layer of the following composition, a support of a cellulose triacetate film base having coated thereon in order from the support a red-sensitive silver iodobromide emulsion layer containing N-n-dodecyl-1-hydroxy-4-chloro-2-naphthamide as a cyan coupler, a gelatin intermediate layer, a green-sensitive silver iodobromide emulsion layer, containing 1-phenyl-3- dodecylamino-S-pyrazolone as a magenta coupler, a yellow filter layer containing colloidal silver, a blue-sensitive silver iodobromide emulsion layer containing 4-dodecyl benzoyl-2-methoxy-acetanilide as a yellow coupler and a gelatin protective layer, was immersed for' 30 seconds in a 1% aqueous solution of the compound of this invention (Compound No. 1, No. 2, No. 6, No. 8, No. 10, No. 11, or No. Also, for the purposes of comparison, the same color photographic high-sensitive film was immersed in a 1% aqueous solution of saponin or saccharose monolauric acid ester to provide comparison samples.

After drying the photographic film sample thus immersed, each of the samples was adjusted to a relative humidity of 40% and the amount of the static marks formed was measured in the same manner as described in Example 1. From the amount of static marks, the antistatic properties were evaluated. Ihe results obtained are shown in the following table.

TABLE 6 Charged (volts) Compound:

D Saccharose monolauric acid ester- D As is clear from the results shown in Table 6, it was confirmed that when a photographic film was treated in an aqueous solution of a compound of this invention, either no or less formation of static marks was observed.

From the examples shown above, it will be clearly understood that the compounds used in this invention show excellent antistatic eflects in each case.

While the invention has been described in detail and in terms of various embodiments, it will be appreciated that modifications and variations can be made therein without departing from the spirit and scope thereof.

What is claimed is:

1. A photographic light-sensitive material having antistatic characteristics comprising a support containing thereon at least one silver halide photographic emulsion layer, and at least one subsidiary layer wherein at least one of the layers comprising said photographic light-sensitive material contains an ester deriavtive of an alphasulfofatty acid represented by the general formula attoly to... 1

wherein R represents a saturated or unsaturated, branched or straight chain aliphatic group having more than 6 carbon atoms; M represents a hydrogen atom, an alkali metal atom, or a quaternary ammonium group; Y represents a residual group containing from 2 to 18 carbon atoms and having at least one hydroxyl group; and n represents an integer of from 1 to 7.

2. The photographic light-sensitive material as set forth in claim 1, wherein said residual group is a residual group derived from a multihydric alcohol selected from the group consisting of ethylene glycol, polyethylene glycol, 1,4-dicyclohexane dimethanol, glycerol, 1,2,4-butanetriol, 1,2,6-hexanetriol, trimethylol propane, sorbitol, sorbitan, 2,2,6,6-tetrarnethylol cyclohexanol, pentaerythritol, saccharose, and raflinose.

3. The photographic light sensitive material as set forth in claim 1, wherein said aliphatic group is an alkyl or alkenyl group having from about 6 to 20 carbon atoms.

4. The photographic light-sensitive material as set forth in claim 1, wherein said ester derivative is present in the photographic material at a level ranging from about 0.01 to about 2.0 g. per square meter of the photographic material.

5. The photographic light-sensitive material as set forth in claim 1, wherein said ester derivative is in a protective layer.

6. The photographic light-sensitive material as set forth in claim 1, wherein said ester derivative is in an antihalation layer.

7. The photographic light-sensitive material as set forth in claim 1, wherein said ester derivative is in a silver halide photographic emulsion layer.

8. The photographic light-sensitive material as set forth in claim 7, wherein said ester derivative is incorporated into said photographic emulsion layer by addition to the emulsion coating composition for said layer before coatmg.

9. The photographic light-sensitive material as set forth in claim 7, wherein said ester derivative is incorporated into said photographic emulsion layer by immersing said photographic film after forming said photographic emulsion layer on a support in an aqueous solution containing said ester derivative.

References Cited UNITED STATES PATENTS- 3,516,835 6/1970 MacKey et al. 96-1145 3,547,643 12/1970 Pechmann 96-87 A RONALD H. SMITH, Primary Examiner US. Cl. X.R. 

